One of the more popular irrigation techniques involves the use of drip irrigation conduit having numerous apertures through which is dispensed controlled amounts of water into the earth adjacent to a row of plants. In this approach, which is commonly referred to as “drip irrigation,” the drip irrigation conduit may be installed either above or beneath the surface of the earth, the latter of which is referred to herein as “subsurface drip irrigation.” Subsurface drip irrigation is particularly advantageous over above-ground irrigation methods because water dispensed from subsurface tubing is not affected by evaporation. Furthermore, subsurface tubing is less likely to be damaged by implements and animals than tubing and other components of above-ground irrigation. For this latter reason, it is often advantageous to install other forms of conduit (e.g., electrical conduit) below the surface of the earth as well.
There are a number of different approaches for installing conduit below the surface of the earth. One approach involves the use of an upright plow having a plow blade, a drop fee tube and a coiled conduit source. In operation, a service operator pushes the upright plow over the surface of terrain in which conduit is to be installed. With respect to drip irrigation, the terrain typically includes a row of plants and the upright plow is pushed adjacent the row. The plow blade cuts a trench in the terrain adjacent the plant row and conduit from the coiled conduit source is top-fed through the drop feed tube into the trench.
While those skilled in the art recognize the popularity of upright plows to install drip irrigation (largely due to its relative inexpensiveness), this particular installation approach has several drawbacks. For example, pushing the upright plows through the ground requires great physical assertion on the part of the service operator. To address this concern, several implementations of the upright plow include a vibratory box that induces an oscillation in the plow blade in order to facilitate the creation of troughs thereby. Still, however, some physical assertion is required to create the troughs even though to a lesser extent and, as such, the incorporation of vibratory boxes to the upright plows is not the be all end all solution. Furthermore, conventional upright plows only allow for the installation of a single conduit at a time, and consequently, the physical assertion required by the operator must be repeated for each row of plants that require drip irrigation.
Tractor-implemented plow designs provide a solution to both of the above-noted drawbacks to upright plows. In these designs, a tractor is provided with a structure having multiple plow blades, multiple drop feed tubes and multiple coiled conduit sources. Such a design is described in U.S. Pat. No. 4,447,173 issued to Charles R. Shultz et al. and entitled “Apparatus for Burying Drip Irrigation Tubing.” This particular plow implementation is used to install drip irrigation conduit into beds between furrows in a terrain being used to harvest crops. To accomplish this, the plow includes multiple furrow tracking members, with one furrow tracking member being located on each side of the plow blades. In operation, the furrow tracking members ride in the furrows as the tractor moves forward thereby maintaining the contour of the crop beds while the plow blades create trenches therein. Concurrently, conduit from the multiple coiled conduit sources is fed through the drop feed tubes into the created trenches.
The Shultz design is particularly effective for installing multiple strands of drip irrigation conduit into terrain in which crops have been planted between furrows. However, this design is not well suited for the installation of conduit into non-furrowed terrain, such as lawns, playing fields, construction ground, etc. Furthermore, even with the use of this design in furrowed terrain, Shultz's multiple plow structure is limited in that if any one of the plow blades or furrow members encounters an obstacle (e.g., rock, tree root, etc.), the physical confrontation of that plow blade or furrow with the obstacle is communicated through the structure to all of the plow blades, thereby affecting all troughs under creation.